Imaging techniques like photography and filming using visible, infrared or ultraviolet optical radiation are generally known in the art and commonly used to image, measure and characterize the surfaces of tissue. Optical imaging techniques have also been described to detect and display anatomical structures buried beneath the surface of biological tissue.
Principles for optical imaging techniques to detect and display the value of physiological parameters (such as heart beat rate, respiratory rate, pulse oximetry, etc) have also been described. Some of these principles offer a combination of anatomical imaging and physiological parameter imaging as for example disclosed in WO10/15597. Said publication discloses an imaging apparatus for imaging buried structures using various infrared wavelengths. The absorption ratios are used to derive the oxygenation of blood and other physiological parameters of interest.
One of the problems associated with said imaging apparatus and other prior art imaging techniques, is that calibration is difficult. For true calibration controlled oxygen studies on volunteers are performed which is costly and laborious. While phantom devices in the art are known to test certain functionality of imaging devices, they are generally static in nature and not reliable to reproduce clinically viable solutions for testing the imaging devices. One known device is described in U.S. Pat. No. 6,400,973. An electronic device is disclosed mimicking an arterial blood pulse using a polymer dispersion liquid crystal device. However, this device is not designed for testing the imaging performance of an imaging apparatus.